diff --git a/tests/gem5/replacement-policies/run_replacement_policy_test.py b/tests/gem5/replacement-policies/run_replacement_policy_test.py
index 10061094b4..31076c6d99 100644
--- a/tests/gem5/replacement-policies/run_replacement_policy_test.py
+++ b/tests/gem5/replacement-policies/run_replacement_policy_test.py
@@ -85,6 +85,7 @@ motherboard = TestBoard(
 )
 root = Root(full_system=False, system=motherboard)
 
+motherboard._pre_instantiate()
 m5.instantiate()
 
 generator.start_traffic()
diff --git a/util/gem5art/artifact/gem5art/artifact/artifact.py b/util/gem5art/artifact/gem5art/artifact/artifact.py
index 91ffc64e50..46664e82fb 100644
--- a/util/gem5art/artifact/gem5art/artifact/artifact.py
+++ b/util/gem5art/artifact/gem5art/artifact/artifact.py
@@ -158,7 +158,7 @@ class Artifact:
         documentation: str,
         inputs: List["Artifact"] = [],
         architecture: str = "",
-        size: int = None,
+        size: Optional[int] = None,
         is_zipped: bool = False,
         md5sum: str = "",
         url: str = "",